Artificial tooth



I. E. ROSE.

ARTIFICIAL TOOTH.

APPLICATION FILED SEPT.2II I92I.

Patented July 18, 1922.

2 SHEETS-SHEET I.

mm my J. E. ROSE.

ARTIFICIAL TOOTH.

APPLICATION FILED SEPT.21, 1921'.

Patented m 18, 1922.

2 SHEETS-SHEET 2.

STATES OFFICE.

JOSEPH ELON ROSE, 0F PORTLAND, OREGON.

' ARTIFICIAL TOOTH.

tember 21, 1921.

T 0 all whom it may concern Be it known that I, JOSEPH ELoN Rose, a citizen of the United States, residing at Portland, county of Multnomah, State of Oregon, have invented a certain new and useful Improvement in Artificial Teeth, of which the following is a specification.

The present invention relates to artificial teeth and has to do more particularly with artificial teeth wherein a crown of gold or other suitable material is provided with a facing of porcelain or like material shaped and colored. to simulate a natural tooth. The invention is directed .to the production of a new and durable tooth structure.

One object of the invention is to produce an artificial tooth which shall be strong and durable while presenting a neat finish closely simulating a natural tooth. Another object is to produce a novel structure which shall include only a crown and facing which accurately and firmly fit and engage each other. Another object is to so shape the engaging portions of the crown and facing that the latter will be firmly retained in place under all the varied conditions of service. I

The present application is a division of my prior application, Serial No. 415,258, filed October 7, 1920. g

In carrying out my invention, I provide a crown of one metal throughout which has a front wall comprising a central protruding portion more or less surrounded by a peripheral groove or grooves. Thefacing of porcelain or like material is shaped so as to accurately fit said protruding portion and grooves and to bear against the same throughout its entire engaging surface. The process for bringingabout' this result includes several operations. In performing my process I first form a crown so as to fit the prepared tooth and cut away a portion of its face. With the crown in position upon the prepared tooth I then press warm wax into the opening againstthe tooth. A facing of porcelain or like material is then pressed against the soft wax and the surplus wax trimmed off. The crown, wax and facin may then be removed from the tooth. A ter the facing is removed from the wax, a mold is made'to fit the assembled crown and wax, the crown and wax serving as a pattern. Then the wax is removed from the crown by heating the mold. Then molten Specification of Letters Patent.

Patented July 18, 1922.

Divided and this application filed Sepgold or other metal is poured into the mold and the gold occupies the space formerly occupied by the wax. As a result the open face of the crown is closed by a metal wall which accurately fits bot-h the tooth and facing and to which the facing may be readily attached by cement.- Thefacing, itself, is made from abaked -porcelain form by grinding it to the desired shape. 7

It will be seen that in carrying out my invention I am enabled to produce a crown having a porcelain or like facing which may be used on vital teeth. It will also be seen that the metal wall between the facing and the prepared tooth conforms exactly to the irregularities of both the tooth and the facing and thus provides an accurate fit which enables the parts to be readily secured together by cement. Furthermore, the protruding portion of the front wall of the crown together with the peripheral groove and the co-operating surfaces on the, facing give the assembled structure a strong and retentive form which greatly strengthens the crown and thereby increases its life and durability. Not only is this true, but by the method I employ, the cutting away of the tooth in preparing it is reduced to a minimum, as it does not need to be shaped so as to fit a particular wall. The construction is such also that the crown may be used as an abutment or anchor for a bridge. There are other features and advantages which will be more particularly pointed" out hereinafter while others need not be mentioned since they will be at once apparent to dentists and others skilled in' this art.

The invention in its various features and aspects will be more fully understood upon reference .to the following detailed description taken in connection with the accompanying drawing, and the scope of the invention will be particularly pointed out in the appended claims.

In said drawing, Fig. 1 is a perspective view of an artificialtooth or crown constructed in accordance with the present in vention; Fig. 2 is a vertical section of the crown showing the front cut away so as to provide an open face; Fig. 3 is a similar view of the same crown placed upon the prepared tooth and the open face filled with wax; Fig. 4: is a similar view showing the facing pressed up into engagement with the wax; Fig. 5is a view of the crown and wax, with the facing removed, secured to the sprue wire in the crucible former; Fig. 6 is a sectional view of a ring mold filled with investment material and the wax burned out, all ready for the pouring of the metal; Fig. 7 is a sectional view of the finished crown removed from the mold, its open front now being closed by a metal wall; Fig. 8 is a similar view of the finished tooth showing the facing secured to the outer surface of the metal wall; Fig. 9 is a perspective view of the finished crown with the facing re moved; Fig. 10 is a section through the crown in position upon the prepared tooth, the section being taken on a plane indicated by the line 1010 of Fig. 8; Fig. 11 is a perspective view of the crown when in the condition shown in Fig. 2; Fig. 12 is a perspective view of a modified tooth, showing a crown and facing of somewhat different shape; Fig. 13 is a vertical section of the crown of said modified tooth, showing the front of the crown cut away so as to provide the open face; Fig. 14 is a perspective view of the same crown after the metal has been poured to form the front wall; Fig. 15 is a section through the finished modified crown in position upon the prepared tooth, the section being taken on a plane indicated by the line 15-15 of Fig. 13. Throughout these views like characters refer to like parts.

Referring to the drawing in detail, 9 designates a crown of gold or other suitable material which may be made in any preferred way. According to one method of forming a crown the distance around the prepared tooth 10 is measured at the gum line by a fine wire and a strip of gold is then out according to the length of this wire and its ends brought together and soldered or otherwise secured together so as to form a; band. This is then placed upon the tooth and trimmed, festooned and otherwise shaped so as to bring about the desired fit. Obviously other ways of producing the crown may be employed. When the crown is produced its face is cut away so as to provide an opening 11. When the open faced crown is upon the tooth this opening is positioned so as to expose the labial face of the prepared tooth. While the crown is in this position upon the tooth a quantity of warm and plastic wax 12 is placed over the tooth at the point where the opening is and the opening is well filled with the wax. Then the facing 13 which has previously been prepared is pressed against the soft wax until the facing has been brought into its desired position, and

the surplus wax is trimmed away. The crown, wax and facing are then removed'as a unit from the tooth and a mold is prepared. This mold consists of two parts composed of the usual investment material employed by dentists forthis class of work. One part of the mold, designated 14:, is made by filling the interior of the crown while the wax and facing are in position, with the investment material and allowing it to harden or set. This portion of the mold then takes the place of the prepared tooth and has the same shape as the tooth. At this stage the facing is removed from the crown. The other portion of the mold, designated 15, is formed by enclosing the form 14 with the crown 9 and the wax 12 upon it, with investment material in a suitable receptacle. In the case illustrated, the receptacle comprises a ring 16 having a crucible former 17 provided with a central opening for a sprue 19. The form l t with the crown and Wax upon it is then attached to the end of the sprue 19 by the wax. Invest ment material is applied to the crown upon the sprue in the usual manner, and then the ring 16 is placed on the crucible former, over the crown, and filled with investment. This leaves all the parts carried by the sprue completely surrounded by the investment material 15. When the investment material has set, then the crucible former 17 and the sprue 19 are removed, leaving the sprue canal 20. The ring and its contents are then heated and the wax melted and driven off, leaving the void 21 which is to be filled with molten metal. When pouring the metal, the ring and-its contents, as illustrated in Fig. 6, is set on the exhaust stand 22 of a suitable exhausting machine. The exhausting a-ir passes through the pores of the investment material and causes the molten metal, as it "is poured, to enter all portions of the void 21. Although I have described the casting operation as one using an exhaust, other casting methods may be employed. When the metal is poured in this way it fuses with the metal of the crown and provides a solid metal wall 23. This wall closes the opening in'the face of the crown 9 and both its front surface and its rear surface have the same shape as did the wax. Consequently, the front face of the wall 23 has-a surface which closely and accurately fits the rear wall of the facing 13. Similarly the rear face of the wall 23 accurately fits the adjacent surface of the prepared tooth 10. It will be noted also that the front wall 23 comprises a central protruding portionbounded by peripheral grooves 24. These grooves serve to hold the facing upon the tooth with greater certainty, and the walls of the groove, especially that near the incisal edge of the tooth, serve to transmit the strain of impact upon the facing 13 to the crown 9. In this form of the invention, the overlap of the facing about the incisal edge of the crown greatly improves the esthetic appearance of the finished structure. The two facings are to be used for different types of teeth, long and short. When the metal forming the wall 23 has cooled, the crown with its new wall may he removed from the precise details disclosed but aim to cover by the terms of the appended claims all the mold. It is then a simple matter to aflix the crown to the prepared tooth by cement. In like manner the facing 13 may be secured to the wall 23 by cement. 7

As before noted I make the facing 13 out of ready-baked porcelain by grinding the same to the desired shape. It will be obvious that crowns of different types of manufacture may be employed. The facings may also be made in different ways and they may also be variously shaped. In any event they should ordinarily be made to cover all the metal of the crown as the tooth is viewed when looking toward the labial surface. In the structure which I have heretofore described, the facing extends over the incisal edge 25 of the crown, overlapping it slightly. As illustrative of a modified arrangement, I have shown a structure in Figs. 12 to 15, inclusive, wherein the crown 9 is provided with an opening 11 which extends only to the incisal edge 25. of the crown. When the crown is completed by the addition of cast wall 23', that wall does not go beyond or include the incisal edge but is of the same length and outline as the opening 11. In this structure the lower groove 24, or, if you please, the incisal portion of the peripheral groove 24, has a wall 26 which receives the pressure applied to the incisal edge of the facing 13. There are, as before, the vertical portions of the peripheral groove 24 into which the vertical portions of the peripheral ribs of the facing 13' accurately'fit. These grooves in'both illustrated forms of the invention co-operate with the corresponding projections or ribs upon the facing to firmlyhold the latter in place when subjected to the strains and shocks due to the use of the tooth. In the modified form the wall 26 of the groove 24' receives the greater portion of the strain to which the facing 13 is subjected. In the first form of the invention the strain is taken up more directly by the portion of the wall 23 at the incisal edge 25. Obviously such changes as here disclosed and others of like character may be made without departing from the spirit and scope of my invention. Obviously, too, the configuration of the facing may be greatly varied. The size of the opening may also be varied. Other changes and alterations will suggest themselves to dentists and others skilled in this art. I therefore do not wish to be limited to the modifications and variations which properly come within the scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An artificial tooth comprising a thin metal crown having Walls adapted to closely envelop the end and sides of a prepared natural tooth and to be trimn'ied and shaped to fit closely against the lingual, labial and other surfaces of the same; the labial crownw-all comprising a central protruding portionpartially surrounded by a receding peripheral groove; a relatively thin labial facing accurately fitted and cemented to the protruding and groove portions of the labial crown-wall throughout the entire engaging surface and extending to its incisal edge; the rear surface of the facing and the outer and inner surfaces of the labial crown-wall being irregular, the irregularities of the rear surface of the facing being counterparts of the irregularities of the outer surface of the labial crown-Wall and the irregularities of the inner surface of the labial crown-wall being counterparts of the irregularities of the labial surface of the prepared natural tooth, the mated counterparts corresponding reversely to each other thus providing intimate and exact fitting at all points; and the labial crown-wall providing a portion directly behind the incisal edge of the facing, considered in the direction of the tooths axis, forming an impact-receiving wall to transmit to the crown, impact and strain applied to the facing at its incisal edge.

2. An artificial tooth comprising a thin metal crown having walls adapted to closely envelop the end and sides of a prepared natural tooth and to be trimmed and shaped to'fit closely against the lingual, labial and other surfaces of the same; a relatively thin labial facing accurately fitted and cemented to the outer face of the labial crown-wall throughout the entire engaging surface and extending to its incisal edge; the rear surface of the facing and the outer and inner surfaces of the labial crown-Wall being irregular, the irregularities of the rear surface of the facing'being counterparts of the irregularities of the outer surface of the labial crown-wall and the irregularities of the inner surface of the labial crown-wall being counterparts of the irregularities of the labial surface of the prepared natural tooth, the-mated counterparts corresponding reversely to each other thus providing intimate and exact fitting at all points; and the labial crown-wall providing a portion directly behind the incisal edge ofthe facing, considered in the direction of the tooths axis, formingan impact-receiving wall to transmit to the crown, impact and strain applied to the facing at its incisal edge.

JOSEPH ELON ROSE. 

